Eccl 3:11 says God set “the world in their heart, so that no man can find out the work that God maketh.” This sentence is enigmatic not just because of the ambiguity of the sentence but also of the translation.
This featured phrase “vanity of vanities” (הבל הבלים habel habalim) that Qohelet repeatedly cries out is considered to be a Hebrew expression of the superlative. But the expression normally comes with the definite article on the second word unlike the case in Ecclesiastes. So is it really superlative?
The main character of the book of Ecclesiastes is known as “the preacher.” But the contents of the book does not correspond to what an ordinary preacher of a local church would say. The book is rather progressive and extreme than conservative.